Having one child makes you a parent, having more than one makes you a referee.

By giving your first born younger siblings, you hope that they will get an instant playmate and best friend. You have visions of them playing happily together, holding hands and giving each other big squeezy cuddles.

It can be a bit of a shock when, instead, your days seem to be filled with soothing sibling squabbles and your kids continually wind each other up.

For any parent in the midst of negotiating sibling spats, the findings of a recent study will be music to your ears.

The new study, published in scientific journal Child Development, found that siblings actually make each other nicer people. Childhood bickering might be part and parcel of having more than one child. But as they grow up together, siblings teach each other to be kind and to care more about the feelings of others.

Siblings teach one another empathy

Researchers followed 452 pairs of siblings, ranging from 18 months to 4 years old, from a variety of different backgrounds over a period of 18 months.

Using video recordings and parent questionnaires they examined their interactions with one another. At the end of the study they also did a test to see how the children reacted to an adult who was in distress (after breaking a cherished object) or in pain (after banging their knee).

The study found that older siblings shape their younger sibling’s development by teaching them to be more empathetic.

What came as a surprise to researchers was that the influence seemed to be reciprocal and younger siblings teach their elders empathy too. In short, both siblings help each other to be kinder and more caring. Marc Jambon, lead researcher of the study said:

Although it’s assumed that older siblings and parents are the primary socializing influences on younger siblings’ development (but not vice versa), we found that both younger and older siblings positively contributed to each other’s empathy over time.

The benefits begin from an early age

This study is also one of the first to show that the positive effect siblings have on each other begins from a very early age.

Laurie Kramer, a professor of applied psychology at Northeastern University commented on the study, saying:

What I find remarkable is the demonstration that children under the age of three do play a meaningful role in shaping their elder siblings’ empathetic concern. We don’t ordinarily think that three-year-olds can have this kind of influence on their older siblings, but they can.

Even the fights help them learn

Both older and younger siblings gain so much from each other as they go through childhood. Both teach each other vital skills to shape one another as a person.

Psychologist Victor Cicirelli  explores this reciprocal relationship in his book Sibling Relationships Across the Lifespan. He writes:

the older sibling gains in social skills in interacting with the younger…the younger sibling gains cognitively by imitating the older.

Even when siblings fight they are learning valuable skills, to stand them in good stead as they go through life. Conflict with siblings teaches them how to interact with friends, peers and co-workers for the rest of their lives.

Sisters are doing it for themselves

The benefits of having a brother or a sister last well beyond childhood too. There was a study by Brigham Young University  which found that having a sister is good for your mental health.

The research revealed that having a sister protected adolescents from feeling lonely, unloved, guilty, self-conscious and fearful.

It doesn’t matter if it’s an older sister, a younger one or if there’s a big age gap – just having a sister seems to provide protection against some of the stress and pressure of the turbulent teenage years. Which is pretty amazing.

But brothers rule too

Let’s not discount brothers though. They play an important role too.

The same study found that having either a brother or a sister makes siblings more likely to carry out kind deeds. They also look out for or show more empathy for others.

It showed that siblings seem to have more influence on one another when it comes to teaching each other kindness than their parents do. Padilla-Walker, key researcher of the study gives this advice to parents:

For parents of younger kids, the message is to encourage sibling affection. Once they get to adolescence, it’s going to be a big protective factor.

Siblings make us happier as adults too

So far research has shown how siblings can have a positive effect on one another in the early years, through school and as teenagers. However it doesn’t stop there. The positive effects of a close sibling bond last later into life.

Studies have shown that having a close bond with a sibling in middle or old age can make each one happier and healthier.

By the time we’re adults, our siblings are the people we know best in the world. They are the ones who have been by your side right through life and who share your history.

Even if they wind each other up and bicker though their childhood years, many siblings count each other as best friends as adults.

Talking to NPR Radio, Robin Marantz Henig, explains just how much he values his brother now they are both grown ups. He says:

Paul and I kind of irritated each other when we were kids; I would take bites out of his precisely made sandwiches in just the spot I knew he didn’t want me to, and he would hang around the living room telling jokes when he knew I wanted to be alone with the boy on the couch.

But as adults, we’ve always had each other’s backs, especially when it comes to dealing with our mother’s health crises, which have become more frequent in the past few years. Paul is the first person I want to talk to when there’s something that worries me.

The research into the positive effects of having a sibling point pretty conclusively to the fact that they make each other happier, healthier and kinder.

So next time you’re refereeing a massive sibling quarrel, take heart in knowing that it’s probably doing them a world of good in the long term!